Sub class will allocate seperate memory for super class instance variable?

class A
int i, j;
void showij()
System.out.println("i and j: " + i + " " + j);
class B extends A
int k;
void showij()
System.out.println("i and j: " + i + " " + j);
what is size of class B will it be just 4 byte for k or 12 bytes for i, j and k ?
will be a seperate copy of i and j in B or address is same ?
thank u

amit.khosla wrote:
just to add on...if you create seprate objects of A and B, so the addresses will be different. We cant inherit objects, we inherit classes. It means if you have an object of A and another object of B, they are totally different objects in terms of state they are into. They can share same value, but its not compulsary that they will share same values of i &j.
Extending A means to making a new class which already have properties & behaviour of A.
Hope this help.That is very unclear.
If you create two objects, there will be two "addresses", and two sets of member variables.
If you create one object, there will be one "address", and one complete set of non-static member variables that is the union of all non-static member variables declared in the class and all its ancestor classes.

Similar Messages

Private or Protected access for super class variables

What is the best practice...
Assume there is a class hierachy like
Person (Super class) / StaffMember/ Professor (Sub class)
1) The best way is to keep all the instance variables of each and every class private and access the private variables of super classes through subclass constructors (calling "super()")
Ex:-
public class Person {
private String empNo;
public Person (String empNo) {
this.empNo = empNo;
public class Professor extends Person {
private String ........;
private int ...........;
public Professor (String pEmpNo) {
super(pEmpNo);
OR
2)Changing the access level of the super class variables into "protected" or "default" and access them directly within the sub classes...
Ex:-
public class Person {
protected String empNo;
public Person () {
public class Professor extends Person {
String ........;
int ...........;
public Professor (String empNo) {
this.empNo = empNo;
Thank you...

i'd think that you'd be better off relaying your initial values through the super class's constructor that way you'll get cleaner code, there's a possibly of inconsistency with option 2. i.e. you can then write code in your super classes to generally handle and properly initialize the instance variables while in the case of option 2, you'll have arbitrary constructors performing arbitrary initialization procedures

Constructor of derived-class has to call constructor of super-class?

In java, constructor of derived-class has to call constructor of super-class? there is no way to omit this step?

Correct. If you do not explicitly call the constructor, a call to the no-arg c'tor, super(), is automatically inserted.
It would be a mess to have it any other way. You'd be creating objects that are not completely initialized. They'd be in an invalid state.
Constructor rules:
1) Every class has at least one ctor.
1.1) If you do not define an explicit constructor for your class, the compiler provides a implicit constructor that takes no args and simply calls super().
1.2) If you do define one or more explicit constructors, regardless of whether they take args, then the compiler no longer provides the implicit no-arg ctor. In this case, you must explicitly define a public MyClass() {...} if you want one.
1.3) Constructors are not inherited.
2) The first statement in the body of any ctor is either a call to a superclass ctor super(...) or a call to another ctor of this class this(...) 2.1) If you do not explicitly put a call to super(...) or this(...) as the first statement in a ctor that you define, then the compiler implicitly inserts a call to super's no-arg ctor super() as the first call. The implicitly called ctor is always super's no-arg ctor, regardless of whether the currently running ctor takes args.
2.2) There is always exactly one call to either super(...) or this(...) in each constructor, and it is always the first call. You can't put in more than one, and if you put one in, the compiler's implicitly provided one is removed.

Which way is used to allocate/deallocate memory for locals?

Good afternoon.
I would like to know how memory is allocated/deallocated for local variables in an activation record/frame. For example, in the following java code:
1 public void test()
2 {
3     {
4          {
5               String y = "abc";
6          }
7     }
8     {
9          String y = "pqr";
10     }
11 } At line 5, memory is allocated for variable y. Is this memory deallocated at line 6 (right after its declaration block), or after the line 11 at which point the whole activation record for the method is popped out of the stack?
In addition, is this local memory allocation/deallocation strategy required by the Java specification, or could be different with different Java compilers? Thank you very much and have a great weekend,
Sunny

Hi,
Thank you for your comments!
Perhaps I did not state my problems clearly. Here is my real purpose: I am trying to monitor a program's runtime behavior by dynamically maintaining an object graph where nodes represent runtime objects and directed edges represent "refer to" relation between objects. To better understand my questions, let me first briefly introduce my algorithm to update the object graph:
1. add an edge (between objects): when a local refers to an object, add an edge from the enclosing object to the referred object
2. delete an edge: when a local refers to another new object, delete the edge from the enclosing object to the previously referred object; or the memory allocated for this local is deallocated.
For example, if I have the following Java method,
1 m()
2 {
3        {
4                 Object x = objA;
4'                x = objB;
5                 // some statements
6        }
7        {
8                 // some statements
8'                Object x = objC;
9        }
10 }Below, the enclosing obj means the object containing the method m().
At line 4, a local name x is declared and assigned objA, at which point an edge from the enclosing obj to objA should be added. At line 4' the same local is assigned a new value, at which point we should delete the edge from the enclosing obj to objA and add a new edge to objB.
At line 6 this local is out of its scope, whether or not we should delete the edge from the enclosing obj to objB depends on whether the memory allocated for x is deallocated.
Lastly, at line 8' a new local with the same name x is declared so we should add a new edge...
Another example is like this:
1 m1()
2 {
3      Object x = objA;
4     // some statements
5     m2();
6 }
7 m2()
8 {
9     Object x = objB;
10     // some statements
11 }After line 9, I should be able to know the enclosing obj has two outgoing edges labeled with x, one is to objA and the other is to objB.
Is there any solution to getting this runtime information for Java local variables? I would really appreciate any help!
-- Sunny

HT5525 I am ordering 27 seperate books for my class. I am a teacher. I dont want to have to pay the shipping cost for every book. Is there any way I can pay one shipping cost and you can send me all th books at the same time? Thank you. Linda Gleichm

I am a teacher and I am sending 27 books to be published. I don't want to have to pay postage on each book. Can you send them to me all at once and just charge me one postage fee. I can't aford to pay for postage for each child in my classroom. Thank you.
Linda Gleichmann

1 - we are users just like you - so not we can not do anything about bulk shipping
2 - Apple printing policy is that only multiple copies of the same (identical) book can be ordered in one order with one shipping charge - if you are ordering 27 copies of the same book then there will be one shipping charge for the order - if there are different bookd then there will be a shipping charge for each different order
see http://store.apple.com/us/help/print_products for more information
LN

Regarding Super classes

Hi,
I have created one class in SE24. This class will be used as a super class for other classes.
When subclasses are derived from this superclass, i want to make sure that some of the methods of superclasses are redefined by the subclasse compulsarily.
So i want to force the subclasses to redefine complusarily some of the methods of its super class.
Is this feasible. If so please let me know the corresponding approach.
Thanks in advance !
Pramod

Hi,
Check this out this will help you.
Inheritance is the concept of passing the behavior of a class to another class.
1.You can use an existing class to derive a new class.
2.Derived class inherits the data and methods of a super class.
3.However they can overwrite the methods existing methods and also add new once.
4.Inheritance is to inherit the attributes and methods from a parent class.
Inheritance:
Inheritance is the process by which object of one class acquire the properties of another class.
Advantage of this property is reusability.
This means we can add additional features to an existing class with out modifying it.
Go to SE38.
Provide the program name.
Provide the properties.
Save it.
Provide the logic for inheritance.
*& Report ZLOCALCLASS_VARIABLES                      *
*&----------------------------------------------------*REPORT ZLOCALCLASS_VARIABLES.
*OOPS INHERITANCE
*SUPER CLASS FUNCTIONALITY
*DEFINE THE CLASS.
CLASS CL_LC DEFINITION.
PUBLIC SECTION.
DATA: A TYPE I,
      B TYPE I,
      C TYPE I.
METHODS: DISPLAY,
         MM1.
CLASS-METHODS: MM2.
ENDCLASS.
*CLASS IMPLEMENTATION
CLASS CL_LC IMPLEMENTATION.
METHOD DISPLAY.
WRITE:/ 'THIS IS SUPER CLASS' COLOR 7.
ENDMETHOD.
METHOD MM1.
WRITE:/ 'THIS IS MM1 METHOD IN SUPER CLASS'.
ENDMETHOD.
METHOD MM2.
WRITE:/ 'THIS IS THE STATIC METHOD' COLOR 2.
WRITE:/ 'THIS IS MM2 METHOD IN SUPER CLASS' COLOR 2.
ENDMETHOD.
ENDCLASS.
*SUB CLASS FUNCTIONALITY
*CREATE THE CLASS.
*INHERITING THE SUPER CLASS.
CLASS CL_SUB DEFINITION INHERITING FROM CL_LC. "HOW WE CAN INHERIT
PUBLIC SECTION.
DATA: A1 TYPE I,
      B1 TYPE I,
      C1 TYPE I.
METHODS: DISPLAY REDEFINITION,     "REDEFINE THE SUPER CLASS METHOD
         SUB.
ENDCLASS.
*CLASS IMPLEMENTATION.
CLASS CL_SUB IMPLEMENTATION.
METHOD DISPLAY.
WRITE:/ 'THIS IS THE SUB CLASS OVERWRITE METHOD' COLOR 3.
ENDMETHOD.
METHOD SUB.
WRITE:/ 'THIS IS THE SUB CLASS METHOD' COLOR 3.
ENDMETHOD.
ENDCLASS.
*CREATE THE OBJECT FOR SUB CLASS.
DATA: OBJ TYPE REF TO CL_SUB.
START-OF-SELECTION.
CREATE OBJECT OBJ.
CALL METHOD OBJ->DISPLAY. "THIS IS SUB CLASS METHOD
CALL METHOD OBJ->SUB.
WRITE:/'THIS IS THE SUPER CLASS METHODS CALLED BY THE SUB CLASS OBJECT'COLOR 5.
SKIP 1.
CALL METHOD OBJ->MM1.     "THIS IS SUPER CLASS METHOD
CALL METHOD OBJ->MM2.
*CREATE THE OBJECT FOR SUPER CLASS.
DATA: OBJ1 TYPE REF TO CL_LC.
START-OF-SELECTION.
CREATE OBJECT OBJ1.
SKIP 3.
WRITE:/ 'WE CAN CALL ONLY SUPER CLASS METHODS BY USING SUPER CLASS OBJECT' COLOR 5.
CALL METHOD OBJ1->DISPLAY. "THIS IS SUPER CLASS METHOD
CALL METHOD OBJ1->MM1.
CALL METHOD OBJ1->MM2.
This example will help you to solve your problem.
For more detailed information GOTO -> SAPTECHNICAL ->Tutorials -> Object Oriented Programming.
Regards Madhu.
Code Formatted by: Alvaro Tejada Galindo on Jan 7, 2009 12:13 PM

How to allocate more memory to graphic card

I have Hp probook 6570b with intel hd 4000 graphic card ... i just wanna ask how to change amount of allocated ram to graphic card ... i have no options to do this in bios .

Fastshock wrote:
... i have no options to do this in bios .
Hi,
No, nothing you can do. The system will work this out for you and it will allocate AVAILABLE memory for the GPU if required.
Regards.
BH
**Click the KUDOS thumb up on the left to say 'Thanks'**
Make it easier for other people to find solutions by marking a Reply 'Accept as Solution' if it solves your problem.

Super class for java Language

which is the super class for java Language...
this is an interview question .
I SAY Object is the super class for java Language ...
then he asked whether object class will extend ??
i say Yes it will implectly extend ...
then he whether each and every class will extend object
i say yes ...
then he asked multiple inheritance is possible in java ...
i say no ...
then how will say object class will extend in each and every class....
hai friends if there is any solution tell mem
by
dhana

which is the super class for java Language...
this is an interview question .
I SAY Object is the super class for java Language
ge ...If you mean the ultimate parent of all classes, yes.
(Although it's not the parent of interfaces.)
then he asked whether object class will extend ??
i say Yes it will implectly extend ...Not sure what is meant by "will object extend."
then he whether each and every class will extend
object
i say yes ...Correct.
then he asked multiple inheritance is possible in
java ...
i say no ...Correct. At least in the usual sense. When people talk about multiple inheritance, the usually mean multiple inheritance of implementation, such as C++ supports. The ability to implement more than one interface in Java is sometimes referred to as multiple inheritance of interface. I don't know if that term is in common use outside of Java.
then how will say object class will extend in each
and every class....
hai friends if there is any solution tell memMultiple inheritance means that a class' ancestors are not all in a straight line to the ultimate parent. That is, not all ancestors are parents or children of each other.
You are you father's son, and he is his father's son, and so on. So your grandfather is your ancestor, and so is your father. This is not MI.
You also have a mother. She's neither an ancestor nor a descendant of your father. That's MI.

Overwriting a method of a super class in the subclass ???

Hi,
can somebody tell me whether it's possible to add a new implementation of a method in the sub class which is inherited from a super class?
I want to model my program in that way:
1. I define a super class with some implemented methods.
2. This class should be inherited in a sub class. One method should be used as it was implemented in the super class but another method should be overwritten in the subclass.
I know this concept from Java but I couldn't find a way how to do it in ABAP
Many thanks for any help!
Best regards,
Birgit

hi,
yeas you can do it,
Subclass can re-implement the inherited public and protected methods from superclass.Class C1 contains method METH1(public) and METH2(protected), both of which are modified and re-implemented in its subclass C2.also you can have ur own methods in subclass.Objects are created out of both classes and the method METH1 for both objects are called.
Output of the program demonstrates different behaviour for method METH1 of class C1 and C2.
This demonstrates the theme.
REPORT YSUBDEL.
CLASS C1 DEFINITION.
PUBLIC SECTION.
   METHODS : METH1.
PROTECTED SECTION.
   METHODS METH2.
ENDCLASS.
CLASS C1 IMPLEMENTATION .
METHOD : METH1.
   WRITE:/5 'I am meth1 in class C1'.
   CALL METHOD METH2.
ENDMETHOD.
METHOD : METH2.
   WRITE:/5 ' I am meth2 in class C1 '.
ENDMETHOD.
ENDCLASS.
CLASS C2 DEFINITION INHERITING FROM C1.
PUBLIC SECTION.
METHODS : METH1 redefinition,
meth3.
PROTECTED SECTION.
METHODS : METH2 redefinition.
ENDCLASS.
CLASS C2 IMPLEMENTATION.
METHOD METH1.
   WRITE:/5 'I am meth1 in class C2'.
   call method meth2.
endmethod.
METHOD : METH2.
WRITE:/5 ' I am meth2 in class C2 '.
ENDMETHOD.
METHOD : METH3.
WRITE:/5 ' I am own method of class C2'.
ENDMETHOD.
endclass.
START-OF-SELECTION.
DATA : OREF1 TYPE REF TO C1 ,
         OREF2 TYPE REF TO C2.
CREATE OBJECT : OREF1 , OREF2.
CALL METHOD : OREF1->METH1 ,
                OREF2->METH1.
hope it helps,
regards

Weird one.. i can't return a variable from the extended to the super class

Hey everyone, i hope i'm not annoying you guys :)
So today's problem is to return a variable (int) from a method of the extended class and print it ont the super class.
I'm just testing the super class , if it works fine.
So the extended class ( FileIO) just read the file txt and return the integer or string ( from the txt file)
I already did a main method to that class and tested it, it works fine.
So now the problem is to print the integer ( that the extended class gets from the txt. ) inside the Super class. I mean , is the same thing but now im testing the Super class , just have to do the same thing, a super class method calls the extended class method and receive the integer from the txt file.
i think the problem is when i create the instance of the FileIO object , maybe its constructor ...i don't know.
The name of the txt file is passed from the super class to the extended class, but i think the error is not from there.
this.aero_le = new BufferedReader(new FileReader(super.ficheiroleitura_aero())); // super calls ficheiroleitura_aero() and receive the name of the txt file ( e.g "temp.txt") so i think that is correct.
here's the code of the Super class public class Aeroporto {
     private String filereader_voo = "temporary.txt";
     private String filereader_aero = "temp.txt";
     private String siglaAero = "";
     public FileIO file;
     public Aeroporto(){};
     public Aeroporto(String filereader_voo, String filereader_aero) throws IOException{
          this.filereader_voo = filereader_voo;
          this.filereader_aero =filereader_aero;
          file = new FileIO();
     public String siglaAero() {
          return siglaAero; }
     public String filereader_aero(){
          return filereader_aero;
public int nrLines() throws IOException{   // it was supose to retunr the number of lines ( integer) from the txt file .
          return Integer.parseInt(file.lerLinhaN(1,1));
// main() {
Aeroporto a = new Aeroporto();
          int v = a.nrLines();
          System.out.print(v);
// ***********************************************************+
// Extended Class
public class FileIO extends Aeroporto{
     private String ficheiroescrita;
     private PrintWriter vooescreve, aeroescreve ;
     private BufferedReader voo_le, aero_read;
     public FileIO(){}
     public FileIO(String filereader_voo, String filereader_aero, String ficheiroescrita) throws IOException {
          super(filereader_voo, filereader_aero);
          this.ficheiroescrita = ficheiroescrita;
          //If file does not exists , create one.
          try{
               this.aero_read = new BufferedReader(new FileReader(super.filereader_aero()));
               aero_read.close();
          catch(IOException ex){
               this.aeroescreve = new PrintWriter(new FileWriter(ficheiroescrita));
               aeroescreve.close();
public String lerLinhaN(int line, int column) throws IOException{ // this method works fine , i already tested this class.
          this.aero_read = new BufferedReader(new FileReader(super.filereader_aero()));
          for(int i = 0; i != line-1; ++i) aero_read.readLine();
          String linha = aero_read.readLine();
          String [] words = linha.split(" ");
          return words[column-1];
Maybe the error is that i use to test the Super class a default contructor on both classes... i don't know where the error is, i also did two small classes ( super and another that extends ) and get the string "Hello" from the super and print it inside the extended..and it works, that's why i think the error is when i call the extended class .. need help.
thanks.

Ok,
This one might actually work... atleast it compiles.import java.io.BufferedReader;
import java.io.FileReader;
import java.io.File;
import java.io.PrintWriter;
import java.io.FileWriter;
import java.io.IOException;
public abstract class FileIO {
     public static boolean CreateOutputFileIfNotExists(
          String outputFilename //the name of the file to ensure exists.
     ) throws IOException
          final String functionName = "FileIO.CreateOutputFileIfNotExists";
          boolean retVal = false;
          //If the output file does does not exist then create it.
          //post condition: output file exists or an IOException has been thrown.
          BufferedReader infile = null;
          try{
               infile = new BufferedReader(new FileReader(outputFilename));
               retVal = true;
          } catch(IOException ex) {
               PrintWriter outfile = null;
               try {
                    outfile = new PrintWriter(new FileWriter(outputFilename));
                    retVal = true;
               } catch(IOException ex2){
                    throw new IOException(functionName + ": cannot create output file " + outputFilename, ex2);
               } finally {
                    outfile.close();
                    if (outfile.checkError()) {
                         throw new IOException(functionName + ": error on output stream " + outputFilename);
          } finally {
               try {
                    infile.close();
               } catch(IOException ex){
                    throw new IOException(functionName + ": cannot close output file " + outputFilename, ex);
          return(retVal);
     public static String readLine(
               String inputFilename //the name of the file to read.
          , int     lineNumber    //1 based number of the line to read from.
     ) throws IOException
          final String functionName = "FileIO.readLine";
          String outputLine = null;
          // reads the numbered "lineNumber" from "inputFilename".
          BufferedReader infile = null;
          try {
               infile = new BufferedReader(new FileReader(new File(inputFilename)));
               for(int i=1; i<lineNumber; ++i) infile.readLine();
               outputLine = infile.readLine();
          } catch(IOException ex){
               throw new IOException(functionName + ": cannot read input file " + inputFilename, ex);
          } finally {
               try {
                    infile.close();
               } catch(IOException ex){
                    throw new IOException(functionName + ": cannot close input file " + inputFilename, ex);
          return(outputLine);
     public static String readWord(
               String inputFilename //the name of the file to read.
          , int lineNumber        //1 based number of the line to read from.
          , int wordNumber        //0 based number of the word to read.
     ) throws IOException
          final String functionName = "FileIO.readWord";
          String outputWord = null;
          // reads the numbered space-seperated "wordNumber" from the numbered "lineNumber" of "inputFilename"
          try {
               String[] words = FileIO.readLine(inputFilename, lineNumber).split(" ");
               if (wordNumber>0 && wordNumber<words.length) outputWord = words[wordNumber-1];
          } catch(IOException ex){
               throw new IOException(functionName + ": cannot read input file " + inputFilename, ex);
          return(outputWord);
}Design notes... FileIO is a generic helper class... there is nothing specific to Airports, flights, or any other "domain" specific stuff in it... so it's re-usable... you can keep it and reuse it on other projects, or even share it with your friends.
So... The airport class will just call the static methods on FileIO like this    ....
    int lineNumber=1;
    int wordNumber=1;
    String airportCode = FileIO.readWord(airportsFilename, lineNumber, wordNumber);
    ....How's that?
corlettk: my now mandatory edit.

Accessing super class private variables from derived class

posted November 01, 2005 08:20 PM Profile for kenji mapes Email kenji mapes Send New Private Message Edit/Delete Post Reply With Quote Assume I have a default and a param constructor in both a subclass and a super class. The members are private.
So after validation logic in the sub class param. constructor, I want to access an instance variable of the super class's default constructor to set the subclass's matching variable to the default in the super class.
Is there anyway I can do this. Of course, I have inherited setters and getters.
Thanks.

posted November 01, 2005 08:20 PM Profile for
kenji mapes Email kenji mapes Send New Private
Message Edit/Delete Post Reply With QuoteI suppose this is the result of an attempted crossposting from another forum. :)

What is the best way to capture RGB8 image to memory for later write to disk?

HI-
I have been using the code below for some time now but wonder if an expert can take a look and let me kown if there are ways to improve it. Problem I run into is that I preallocate the memory beforehand (camera.buffering[]), and with a 5 MP camera, this takes up a lot of RAM. It seems like when I am running this program in debug mode all day and constantly start/stop it without allowing it to free the memory gracefully, i eventually bog the system and start getting Out of Memory error -12, in other places in my code such as DisplayBitmap or GetBitmapfrom File. Is this all related to how much memory I am trying to allocate prior to begining the camera capture routine below?  Am I not allocating and free-ing it properly?
Code is below for how I grab the image and then send to memory usign memcpy. Is there a better, more efficient or faster method? I have removed error checking/etc from code below simply to save space. This operates at 15 fps.
I also included my allocation and free-ing code, too.
Thanks in advance.
Blue
//caemra capture loop//
camera.dxerror = IMAQdxGrab (camera.session, camera.image, 1, &camera.bufNum);
stat = imaqRotate2 (rotateimage, camera.image, camera.rotate_image, pixval, IMAQ_BILINEAR, TRUE);
stat = imaqScale (scaledimage, rotateimage, 4, 4, IMAQ_SCALE_SMALLER,IMAQ_NO_RECT);
stat = imaqGetImageInfo(camera.image,&camera.info);
stat = imaqDisplayImage (scaledimage, 0, FALSE);
memcpy (camera.buffering[camera.count], camera.info.imageStart, camera.info.pixelsPerLine*camera.CAMY*camera.bytesperpixel);
//memory allocation code//
camera.buffering = (int **)malloc(camera.maxcount*sizeof(int*));
for(i=0;i<camera.maxcount;i++)
      camera.buffering[i] = (int *)malloc(camera.info.pixelsPerLine*camera.CAMY*camera.bytesperpixel);
// free allocated memory code//
for(x=0;x<camera.maxcount;x++)
        free(camera.buffering[x]);
free(camera.buffering);

How many images are you storing in RAM? Typically when I need to work with tens, hundreds, or even thousands of images, I save them to the hard drive after I capture them as a PNG with 1000 quality. Sometimes I process them before saving, sometimes I process them offline from the saved images depending on the application. If you don't need all of the images simultaneously in memory at once, just save them to PNG. If you only process one image at a time, only allocate enough memory for the processing you need to perform on a single image.
www.movimed.com - Custom Imaging Solutions

Link between Class and characteristics created for that class

Hi All,
Is there any table that I can look at to find a link between class and the characteristics created for that class. For all the list of characteristics created I am refereing to CABN table but my requirement is to find the logic to see all the characteristics created for a class. Can anyone suggest me the right table to look at?
Regards,
Shane

Hi,
I would like to thank you for your quick response. So based on your thoughts, here is the process i followed to find the characteristics for a existing class, took the Internal class number and used the KSML table to find all the Characteristics created for that class.
To find the list of values assigned to that characteristics, used the AUSP table for that characteristics internal number.
Thank you again for your inputs
Shane.

Static Class Function vs. Instance Variables

I'm making a Wheel class to spin the wheels on some toy
trains as they move back and forth.
Each wheel on the train is an instance of the Wheel class and
there are several of them.
I thought it would be great to just have a static class
function to tell all the Wheels to start turning:
Wheel.go();
The Wheel class keeps a static array of all of its instances
so I thought I would just loop through all of those instances and
issue the wheelInstance.roll() method.
So far it all works. But I was planning to use a setInterval
to call the roll() method and each instance has its own rollID
property that I would like to assign the setInterval ID to. Here is
the problem.
Since the rollID is an instance property I can't access them
from a static class function. Is there any way to do this?
Currently I"m just using an onEnterFrame which doesn't require me
to use the instance properties.

Technically yes, realistically for this class no.A
class will probably take several hundred bytes at
least to load, with no data of your own. So adding4
bytes for a int is less than 1% of the total size.
And if you are loading millions of differentclasses
then you should rethink your design.If you don't instantiate the class when you reference
a static variable why would you consume memory for the
class other than the variable itself? I don't
understand what you are talking about with the
"millions of different classes", it's not germane to
the question. Bottom line, referencing a static
variable more than once will save memory.Using a class, static or by instance, requires that the class be loaded. A loaded class creates, at the very least, an instance of java.lang.Class. Any static members of the class are in addition to the storage space needed for the instance of java.lang.Class and for any internal storage needed by the JVM in addition to that.
Thus if one has a static data member when the class is used in any way, the static data member takes storage space. However a member (non-static) does not take storage space.
Of course the meta data for the member could take as much space as the static member so the point could be moot. Is that what you were referring to?

I want to access that BEA instance variable inside of a external java class

Hi,
This is N.pradeep. I am a java programmer, and I am new to BEA AquaLogic BPM studio5.7. I have a question regarding how to retrieve an instance variable of BEA Aqua Logic to an external Java Program. i.e. I want to access that BEA instance variable inside of a external java class, and vice versa.

You can use PAPI or PAPI-WS for accessing BPM instance variable from a Java code, thougt I am not sure how the reverse will be done. Assuming that you are aware aof PAPI-WS and have created the necessary stubs out of the PAPI-WS WSDL using Axis, you can access instance variables using the API's or operations defined therein.
Thanks and Regards
Vivek Nandey
BEA Certified Developer for Integration Solutions
[email protected]

Sub class will allocate seperate memory for super class instance variable?

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